Citrus juice extraction on a commercial scale is advantageously performed with a juice extractor. For example, an inline juice extractor manufactured by the assignee of the present invention includes opposing cups such as upper and lower cups that move relative to one another along a reciprocal path of travel. The sides of both the upper and lower cups typically include fingers that support a fruit so that it can be squeezed without bursting. The fingers of the upper cup interdigitate or intermesh with those of the lower cup. An orange, other citrus fruit or some types of vegetables can be fed, for example, to the bottom cup by a cam-operated feeding device. The upper and lower cups are then brought together so that the respective fingers of the cup intermesh and the fruit therebetween is accordingly squeezed.
Sharp, typically circular, cutters are positioned in the top and bottom cups. As the cups move relative to each other, the fruit is pressed against the cutters, which cut plugs from both the top and bottom portions of the fruit as the interdigitating fingers of the two cups mesh together. The cutting of the plug from the top portion of the fruit promotes separation of the peel from the internal portions of the fruit (i.e., juice and pulp). The plug cut from the lower portion of the fruit allows the internal portions of the fruit to be forced down into a strainer tube positioned just below the lower cup cutter. The strainer tube, in turn, is positioned within a manifold.
After the internal portions of the fruit have been squeezed into the strainer tube, an orifice tube moves upward into the strainer tube applying pressure to the internal portions of the fruit. This causes the juice and juice sacs, due to their small particle size, to flow through small holes of the strainer tube and into the juice manifold, thus separating out the juice and pulp.
Further details relating to the citrus juice extractor may be found in commonly assigned U.S. Pat. No. 5,970,861 to Suter et al.; U.S. Pat. No. 5,992,311 to Suter et al.; U.S. Pat. No. 7,156,016 to Schrader et al.; and U.S. Patent Publication No. 2009/0081338 to Mathews et al., and the entire contents of each reference which are incorporated herein by reference.
One of the design and engineering goals with this type of juice extractor has been to develop components used within the extraction process that will maximize yield and quality and increase productivity in extractor feed efficiency. One method for attaining these goals has been to provide automated systems that measure and control a juice extractor's performance when feeding fruit and extracting juice to ensure high product quality and overall yield. It is therefore desirable to sense or detect when poor fruit feeding or blockage occurs within the various juice extractor components that would negatively affect both juice yield and quality.